Knee joint replacement operations are performed by an orthopaedic surgeon, usually under a general anaesthetic. The alternative is to have an epidural that completely blocks sensation in the leg and enables the patient to stay awake during the operation.
Once the anaesthetic has taken effect, the orthopaedic surgeon makes a single cut about 15-30cm down the front of the knee. The kneecap is moved to one side so the joint is accessible. The worn or damaged surfaces are removed from the thigh and shin bones, and the ends are shaped to fit the artificial knee.
A replacement joint is fitted over both bones. The back of the kneecap may also be fitted with an artificial cap, known as a patellar resurfacing. Once all the new parts are in place, the wound is closed with stitches, and covered with a dressing. The knee will also be bandaged to reduce swelling. The total procedure takes up to two hours.
Benefits of replacement knee surgery
Replacement knee surgical operations are very successful at relieving severe knee pain and improving mobility of the joint. In one study, 9 out of 10 people rated their artificial knee as ‘good’ or ‘excellent’ five years after having surgery. For these people, a replacement knee should last for 10-15 years or longer still.
The initial pain of knee replacement surgery improves after the first week, and usually disappears completely after three weeks. After six months, the new knee is straight, comfortable when walking, and can bend more than 90 degrees.